You're right, of course. In fact, the specs call for a unit to fall within a 
certain range of masses as I recall. Density then affects the volumn.

But my point had to do with a 20 year old student's comprehension of a pint 
and a quart versus her comprehension of a liter. The blood was there merely 
to get the conversation started.

By the way, I took the opportunity in class to point out that a puddle 
covering a square meter at a depth of 1 mm contains a liter. THAT got 
everyone's attention and even the instructor counted out the floor tiles to 
get a feel for that. A depth of 1 mm is probably not too bad an estimate of 
the depth of a pool of blood on a tile floor, I would think.

Jim

On Wednesday, 2003 October 22 13:22, Terry Simpson wrote:
> James R. Frysinger wrote:
> >he mentioned a "unit of blood" stating that it was roughly a pint or half
>
> of a quart.
>
> The amount in a unit is very variable because of how it is collected.
>
> See the sizes of bags come in rational metric sizes, at least for the
> following supplier (I suspect that they all do):
> www.baxterfenwal.com/jsp/products/wholeBloodFamily.jsp
>
> "a unit of blood (about 400 to 500 ml"
> http://clinicalstudies.info.nih.gov/detail/A_1999-CC-0168.html
>
> "one unit of blood (450-500 ml)"
> www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=113
>1 1689&dopt=Abstract
>
> "unit of donated blood (450 mL)"
> www.cdc.gov/ncidod/eid/vol8no8/02-0025.htm
>
>
>
> There is a difference between units collected and units delivered (because
> treatments reduce the volume).
> http://blood-bank.egypt.com/professionals.html

-- 

James R. Frysinger
Lifetime Certified Advanced Metrication Specialist
Senior Member, IEEE

http://www.cofc.edu/~frysingj
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